Diagnostic test systems for motor vehicles containing controllers are generally known. Such controllers may contain on-board diagnostic means. They control and monitor the engine control system and other systems of the motor vehicle. In on-board diagnosis, error codes are generated and subsequently stored. These controllers and the error code memory can be connected to an external diagnostic tester via a motor vehicle-side diagnosis/test plug.
German Patent Application No. 44 46 512 describes a system for performing vehicle tests in which the terminal of the vehicle-side diagnosis/test plug is not connected to a diagnostic tester located in the repair shop via a cable, but via a telephone located in the vehicle itself, so that the error diagnosis codes are transmitted via the mobile wireless network to a location in a repair shop which then performs the test. Thus repair shop stays can be avoided and tests can also be performed with the vehicle in motion. This known device thus replaces the normal cable connection between vehicle and diagnostic tester in the repair shop with mobile communication.
The diagnostic test system according to the present invention having a portable testing device for vehicles, has the advantage over the related art in that it allows global interconnection of the testing device with the motor vehicle, making access to private and public networks, for example, possible. Thus, existing devices can be utilized in a worldwide combination and used for troubleshooting motor vehicles in the field, which would otherwise not be possible without utilizing the infrastructure of mobile wireless services.
According to the present invention, this is achieved in principle by equipping the external portable testing device with a modem and connecting it to a mobile telephone, a hand-held cell phone in particular, in order to troubleshoot via such an interconnected network outside stationary repair shops.
According to an advantageous embodiment of the diagnostic test system according to the present invention, the portable testing device provided with a modem is located in repair and service vehicles of on-the-road automobile clubs, such as ADAC road monitoring vehicles in particular.